Is Re-Topology necessary for Texture Painting?
I'm still new to 3d modelling but i believe the general rule is that for sculptures you always need to retopologize the mesh. If not, the 3d model will lag or crash the computer system when animating or moving it because the mesh is so heavy in topology.
UV-unwrapping the sculpture also becomes impossible to do by hand as there's thousands of different faces and vertices to choose in the UV-Unwrap process. In other words, the sculpture does need to be Retopologized before applying textures.